The frustrated fcc antiferromagnet Ba2 YOsO6: Structural characterization, magnetic properties and neutron scattering studies
- McMaster Univ., Hamilton, ON (Canada). Dept. of Physics and Astronomy
- McMaster Univ., Hamilton, ON (Canada). Dept. of Physics and Astronom
- McMaster Univ., Hamilton, ON (Canada). Dept. of Chemistry
- Univ. of Manitoba, Winnipeg, MB (Canada)
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Neutron Data Analysis and Visualization Division
- Atomic Energy of Canada (AECL), Limited, Chalk River, ON (Canada). Canadian Neutron Beam Centre
- McMaster Univ., Hamilton, ON (Canada). Dept. of Physics and Astronomy; Brockhouse Inst. for Materials Research, Hamilton, ON (Canada); Canadian Inst. for Advanced Research, Toronto, ON (Canada)
- McMaster University
Here we report the crystal structure, magnetization, and neutron scattering measurements on the double perovskite Ba2 YOsO6. The Fm$$\bar{3}$$m space group is found both at 290 K and 3.5 K with cell constants a0=8.3541(4) Å and 8.3435(4) Å, respectively. Os5+ (5d3) ions occupy a nondistorted, geometrically frustrated face-centered-cubic (fcc) lattice. A Curie-Weiss temperature θ ~₋700 K suggests the presence of a large antiferromagnetic interaction and a high degree of magnetic frustration. A magnetic transition to long-range antiferromagnetic order, consistent with a type-I fcc state below TN~69 K, is revealed by magnetization, Fisher heat capacity, and elastic neutron scattering, with an ordered moment of 1.65(6) μB on Os5+. The ordered moment is much reduced from either the expected spin-only value of ~3 μB or the value appropriate to 4d3 Ru5+ in isostructural Ba2 YRuO6 of 2.2(1) μB, suggesting a role for spin-orbit coupling (SOC). Triple-axis neutron scattering measurements of the order parameter suggest an additional first-order transition at T=67.45 K, and the existence of a second-ordered state. We find time-of-flight inelastic neutron results reveal a large spin gap Δ~17 meV, unexpected for an orbitally quenched, d3 electronic configuration. In conclusion, we discuss this in the context of the ~5 meV spin gap observed in the related Ru5+,4d3 cubic double perovskite Ba2YRuO6, and attribute the ~3 times larger gap to stronger SOC present in this heavier, 5d, osmate system.
- Research Organization:
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Spallation Neutron Source (SNS)
- Sponsoring Organization:
- USDOE Office of Science (SC), Basic Energy Sciences (BES)
- Grant/Contract Number:
- AC05-00OR22725
- OSTI ID:
- 1185738
- Alternate ID(s):
- OSTI ID: 1180011
- Journal Information:
- Physical Review. B, Condensed Matter and Materials Physics, Vol. 91, Issue 7; ISSN 1098-0121
- Publisher:
- American Physical Society (APS)Copyright Statement
- Country of Publication:
- United States
- Language:
- English
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